Key Techniques Of Navigation And Control For Autonomous Rendezvous And Docking Of Spacecraft

The rendezvous and docking technology is the key issue to accomplish the spacecraftmaintenance in-orbit, space station supply, and astronauts visiting. Meanwhile, the in-dependent rendezvous and docking spacecraft is consequentially the trend ofrendezvous and docking technology development. Motivated by the practical and realapplication requirements in space engineering, this thesis focuses on the techniques thataim at ensuring autonomous integrity of GNSS navigation signals, improving the accu-racy of navigation solutions and the attitude control algorithms, and enhancing theadaptability of orbit control etc.. The main contributions of this thesis are presented asfollows:1. Algorithms related to RAIM augmentation of GNSS are developed and comparedwith each other. The refined RAIM based on least-square residuals is proposed by in-troducing adjustment coefficients, which significantly improves the fault detectionprobability. The stochastic characteristics of receiver clock bias are investigated as well.A clock bias prediction model is developed with the moving window combined U-Calgorithm and the receiver clock assistant RAIM method is further proposed to enhancethe fault identification rate of navigation satellites.2. Methodologies of space-borne GNSS relative positioning are detailedly investi-gated including cycle-slip detection, ambiguity integer fixing and navigation solutionestimation etc.. By comparing the existing cycle slips detection and repair methods, acombined big and small cycle slips detection and repair algorithm is proposed and isdemonstrated its validity and efficiency in real applications. Based on the LAMBDAmethod, this paper proposes a new ambiguity search algorithm which applies the uncer-tainty mathematics theory to solve integer ambiguity problem. In order to increase theambiguity fixing success rate, methods improving the floating solution are discussedand simulated to give a persuade conclusion, such as carrier-phase smoothed code, con-ic fitting and Kalman filtering with Doppler.3. Non-overshooting attitude control problem of spacecraft is studied. For a class of strictly feedback nonlinear systems, a non-overshooting tracking control law is designedby using a coordinate transforming and the back-stepping method. The designed controllaw can achieve non-overshooting asymptotically tracking of reference pitch angle forspacecraft, even with a non-zero initial condition, and hence overcome the performancelimits of typical, single degree-of-freedom (SDOF) linear control schemes.4. High-precision attitude robust control problem of satellite under uncertain condi-tions is studied. The uncertain factors involve time-varying moment of inertia and ex-ternal input disturbances. Several tracking control laws by full-state feedback and outputfeedback, respectively, are proposed. The super bound of tracking error is given in termsof controller parameters and bound of the derivative of uncertainty. It provides an expli-cit method to choose the controller parameters for achieving a small tracking error.5. The orbit control and its corresponding control design problem in rendezvous anddocking of spacecraft is solved. A distributed control protocol for rotating consensus isproposed and a sufficient and necessary condition is developed under the condition thatthe communication topology is time-varying and the communication time delay factorexists. The research fruits are valuable and can eliminate the dependence on groundmonitoring and control communication during spacecraft rendezvous and docking.